Typically, solder dispensing operations include a pump in communication with a nozzle for dispensing solder onto a workpiece. The solder may either be sprayed through the nozzle by means of the pump, or may be dispensed via gravity through the nozzle.
A common problem in fine-pitch soldering operations is lack of effective control of the dispensed solder. A single nozzle with a large dispenser opening results in a difficult-to-control operation. Attempts to provide a series of nozzles in close proximity to each other have been abandoned due to the tendency of adjacent solder droplets to coalesce, thereby causing inconsistency as the solder solidifies in its desired position. Droplets left over at the end of the nozzle between dispensing operations may, due to surface tension effects, stick to the nozzle and spread and coalesce with adjacent droplets from nearby nozzles.
A further problem experienced with prior art soldering operations is the inability to sufficiently inert the dispenser area, which results in oxidation and premature solidification of the solder. This oxidation can adversely affect the ability of the solder to stick to the workpiece. It is desirable to provide a solder dispensing system which improves inerting of the dispenser area.
It is further desirable to provide a solder dispensing system in which solder can be accurately and evenly applied to a workpiece in a manner in which solder flow is accurately controlled for smooth dispensing.